Burner for fuels containing tetraethyl lead



B. w. 'ruLLls Nov. 2l 1944.

BURNER FOR FUELS CONTAINING TETRAETHYL LEAD Filed Jan. 12, 1942 2Sheets-Shes?l l INVENTOR Boyd W. Tull/Ls.

Nov. v21, 1944. Q w, TULLls 2,363,098 BURNER EOE FUELS `CONTAININETETRAETHYL LEAD Filed Jan. 12. 1942 2 Sheets-Sheet 2 79 INVENTOR Boyd W72H/As. BY

ATTORNEY Patented Nov. Z1, 1944 BURNER FOR FUELS CONTAINING TETRAETHYLLEAD Boyd W. Tullis, Wichita, Kans., assignor to The Coleman Lamp andStove Company, Wichita, Kans., a corporation of Kansas ApplicationJanuary 12', 1942, nserial No. 42u20 9 claims. (ci. 15s-c1) 'Ihisinvention relates to liquid fuel burning appliances and particularlythose for burning low l boiling point' petroleum hydrocarbons such asstraight run gasolines and naptha. However, fuels'of this type are notalways conveniently obtainable and in many localities are not availablewhen needed. Consequently attempts have Y been made to use present dayautomotive or motor fuels as they are always convenient to obtain evenat the most remote outpost of civilization, but fuels of this characterhave not functioned in such appliances for the reason that they containconsiderable solid material such as hydrocarbon gums and coloringmaterials, as well as antiknock compounds, ,for example tetraethyl lead.When' these materials pass through the extremely hot zone pf thegenerating devices of such appliances they clog the generators within avery few hours burning time. 'I'his is attrib uted to carbonizingof thegums and decomposition of the tetraethyl lead within the generator byreason of thel intense heat required to effect complete vaporizatlon ofthe fuel before itis supplied to the burners of the appliances.

It is, therefore, the Vpurpose of the present invention to provide aburner structure and arl rangement thereof which operates satisfactorilyusing automotive fuels containing tetraethyl lead and other extraneousmaterials which ordinarily cause clogging of conventional equipment.

Another object of the invention is to provide a simple and inexpensiveburner structure for a great variety of andheatlng appliances and whichis particularly adapted for military use and for general utility use bymotorists.

hunters, Sportsmen andv exploration partiesfbecause asuitable fuel forthe burner is always near at hand, namely the 'fuel tank of their motorvehicle, aircraft, motor boat, or the like.

Further objects of the invention are to incorporate with theburnerfeaturespermitting use of motor fuels. instant lighting by airvatomization of the fuel, 'a' shield for limiting external coolingeffects upon the bowl of the burner, and e. mechanism for cleaning thedischarge orince of the vaporizer. v l y In carrying out my invention,VI und that automotive fuels and the like-may be used success- 'soientreadily combustible vapor to maintain combustion of the'higher boilingpoint fractions and the tetraethyl lead through contact thereof with theflames resulting from the evolved vapors. 'The burning fuels are thenvcaused to impinge upon surfaces approaching incandescence and spreadthereby into contact with sufficient air to assure complete combustion.

In accomplishing these results', I have p-rovided improved burnerstructure,l illustrated in the accompanying drawingsuwherein:

Fig. 1 is a vertical sectionI through a stove equipped with afuel supplyand burner appa# ratus constructed in accordance with'the presentinvention.

Fig. 2 is an enlarged vertical `section through the burner, vaporlzerand control valve on lthe line 2--2 of F13. 1.

Fig. 3 *is a cross-section through the vaporizer cn the line 3-3 of Fig.2. v

Fig. 4 is a cross-section through the ducting connection between theburner bowl and -wall of the vaporizer.

Fig. 5 is a detail perspective view l'of the burner. Referring moreindetail to the drawings: -l designates a stove equippedl with a burnerand` fuel supplymeans embodying the featurescf the present invention. Itis to be understood, however. that the invention is adaptable to anyheating or cooking appliance which is to be operated witha hydrocarbontype fuel. The stove illustrated in conjunction with my improved burneris one of generalutility type, character' ized by its ease oftransportation and is, therefore, oneA to which\the burner -l isespeciallyadapted.

The specific structure of the s tove is illustrated and described indetail in an application on Porcameswve. med January 12, 1942, serialNo.

426,421, and other than the burner' and fuel supply means and controlmechanisms, constitutes no part of the present invention.

fully by initially vaporlzing l.4 part of the4 fuel,

that is by vaporizing the low boiling point fractions within a vaporizerand discharging the liquidtetraethyl lead and higher point "fracf,

tions lwhich ,contain the gumslfrom the vapor-.- izer in liquid oratomired state. The low boiling Vpoint fractions, or those vapor-ized,`provide suf- `".lihe stove includes a tank 42 for containing fuel to besupplied tothe burner 3 which may be an ordinary motor fuel, forvexample a gaso line blended to have a high octane value and containingan antiknock compound such las tetraethyl lead. The fuel is admitted tothe tank 2 through a filler neck l ordinarily closed by a pressure-tightcap 5. Connected with the tank is a fuel control valve B carrying avaporizer tube l, which ln, turn supportsrthe burner 3. Carried by thetank on an annular bead l is a spider lll having an opening Ilregistering with a threaded bore l2 in a bushing Il, the'bushing I3being heat coni I sealed within an opening i4. Carried by the arms ofthe spider are posts i extending upwardly alongside of the burner andcarrying a grid i3 for supporting a cooking vessel over the flame of theburner 3.

The valve 6 includes a body i1 having an externally threaded leg I3projected .through they opening in the spider and* threaded into thebushing i3 whereby the valve is supported in rigid position on the tankand the spider is anchored in position on the bead 9 by a jam-nut I3threaded on the leg and bearing against the upper surface of the spider,as best shown in Fig. 1. Formed in the leg I8 of the valve body is abore 23, having a threaded portion 2| in whiclrithe threaded neck 22 ofa nipple 23 is threaded. The nipple 23 carries an outer tube 24 whichdepends into the fuelcontained in the -tank and carries a cap 25 on thelower end thereof having an inlet orice 325 located in close proximityto the bottom of the tank. Also carried by-I the nipple 23 is an innertube 21 of smaller size than the outer tube to form` an .annularpassageway 28 therebetween which communicates at its upper end with theair space 23` above thelevel of the liquid in the tank through openings30 so that under certain ditions air is discharged into chamber-3io! thecap 25 to effect atomizationof fuel admitted through the orifice 26. Thempple 23 has an upperbore 32 connecting with the upper end of the innertube through which fuel is discharged into the bore 20 and from the bore20 into a chamber 33 in the valve body. The chamber 33 aligns with-alateral arm 34 of the valvebody having a threaded axial bore 35' and apacking containing chamber 3B. 'v

Formed in the valve' body coaxially with the bores of the arm A34 is aport 31 having connection with an axial bore 38 opening downwardlywithin an axial arm 33 of the valve body through an angularly arrangedport 40. Rotatably mounted within the bores of the arm 34 is a valvestem 4i having a threaded portion 42 engaging' the internal threadsofthe bore 35 and having a conical end 43 arranged so that the pointthereof enters the port 31 for shutting offor throttling ilow of fuel tothe upper bore 36 of the valve body. The outer end of the valve stemprojects from the arm 34 of the valve body 'and carries a knob 44whereby the valve may be rotated to move the conical end 43 thereof toand from Athe portv 31.

Contained within the bore 36 and seated against an internal shoulder 45thereinis a packing 46 retained in sealing relation with the valve stemby a packingnut 41 threaded upon the arm 34 of the valve body. Theconical end of lthe valve is spaced from the threaded portion' 42 by acylindrical portion 46 which, when the valve is closed orslightly'opened, extends across the bore 20 to eilfect depression of athrottling-rod 43, the throttling rod having a head 50 freely mounted inthe bore 23 and provided withan annularcollar 5I for seating one endof'a coil spring 52 having its opposite end seating against the nipple23 for retaining a stem53, on the headof the throttling rod in contactwith the `valve stem. The throttling rod also includes a wire 54`extending downwardly through the bore of the `nipple, through the innertube, and through the inlet orifice 23 whereby the effective area of theorice is limited so that fuel passing therethrough is caused to move atsumcient velocity in proportion to a stream of air being discharged intothe chamber 30 by way of the passage 2 3, producing 7s an atomized fuelmixture, which mixture is dis-l charged through the atomlzer to theburner to start operation of the burner, as later described. Afterstarting'operation, the valve is opened so' the stem 53 rides againstthe conical end of the valve stem responsive to action of the spring 52which lifts the throttling rod out of the inlet Vorifice 26 to allowfull iiow of fuel therethrough to supply the. full demand ofthe burnerand forms a liquid seal to prevent further flow of air downward throughtube 24.v

The upper portion of the axial arm 33 is externally threaded, as at 55.and is provided with a bevellediedge 56 for seating a flared ange 51 onthe base of the vaporizer tube 1. The vaporizer tube includes acylindrical wall portion 53 forming .an internal vaporizing chamber- 53.The wall portion 60 oi' the vaporizer above the cham- Aber 53 issubstantially thicker than the lower portion so asto better retain theamount of `heat necessary in maintaining a selected temperature for.controlling vapcrization of a selected portion oi' the fuel passinginto the vaporizer so that other portions,

the vvaporizer to. clog-, are discharged as an matomized liquid, aslater described. The thickened wall portion of the vaporizer tube isinternally threaded, as indicated at 6I, mounting the threaded neck 32of a nozzle tip 63 having `a relatively small discharge or burnerfeeding orifice 54 opening into a counterbore 65 which allows thefueldischarged from the nozzle to spread within the bowl 36 of the burner 3.The nozzle tip has. an annular shoulder 61 so that when it is threadedinto the thickened end of the vaporizer tube the shoulder seats tightlyagainst the tube to `provide a tight joint.

The burner bowl 66 includes a relatively thick collar or base portion 63formed of heat oo nductive material Aand having an axially threaded bore63 engaging the external threadson the thickened portion of the tube toconnection therebetween and a ready path fo the heat conducted from theburner bowl tothe vaporizer tube. Attention is here directed to the factthat the amount of conductive metal, and

' extent of the thread connection, are accurately determined, as thesefactors govern the temperature at which the. vaporizing tube operates,which in turn determines the temperature of s the liquid fuel beingpartially vaporized. This fuel temperature is maintained below thevaporizing temperature of the liquid tetraethyl lead or non-hydrocarboncompounds which pass throughthe nozzle tip 33 and orifice 34 in liquidform together with the vapbrized portion of the fuel. Only gasolines orlight napthas whose' compositionp'rovides ample fractions of lowtemperature volatility will thus operate, therefore, this invention isdirected to such fuels. So also. any device which has its vaporizeroperating at tem-- peratures sufnciently high to `completelyvaporiitekerosene,- naptha or gasoline.. vwill not accomf plish the` purpose ofmy invention since the lead in solidl form will be deposited within the-va-l porizer, quickly clogging same.

For example, since the boiling point oi' tetraethyl lead isapproximately 400 F. and 450? F. under pressure at which the fuel in mystove isusually subjected during vided a structure which coordinates theelements ofconductivity and radiation to maintain during operation atemperature ofthe fuel being partially vaporlzed at a point whichwillkvaporiae,

that is those normally causing provide a close operation, 1 have prolwithin 'the vaporizing member that major portion of thefuel possessinglow temperature volatility which vapor acting under pressure causestangular cross-section guidingly supported in the bore 38 of the valvebody and has a stem 80 projecting'throughthe vaporizer chamber into auenlarged bore 80 of the nozzle tip which receives a needle 8| ofsufllcient diameter to be project-` y able through the orillce 84. 'I'heclean-@out device the extent of contact of bowl to the vaporizing tube,and the conductivity of the vaporizing tube itself are all coordinatedwith the factor of radiation to maintain the required temperature of thefuel being vaporized es above set forth. The lperiphery of the collar 88has an annular shoulder encircling a flange 1| encircling the threadedbore 89 thereof in spaced relation with the nozzle tip. The burner bowlhas an upwardly and outwardly curved lower portion 12 of substantiallysemispherical shape, an outwardly. flaring upper portion 13, and anintermediate corrugated belt portion 14. The inner surface of theflaring portion 13 is contacted by flames resulting from ignitionof thefuel and impinging against 4a defiector plate 15.

The deflector 15 includes a substantially concavoeconvex member ofsmaller diameter than -the flange portion of the bowl so that theperiphery` thereof cooperates with the flare ofthe bowl in forming anannular flue-like passageway for the deflected flames and to effectdraft of cornbustion supporting air into the burner bowl through airinlet openings 18 in the semispherical portion thereof, the .member 15being turned so thatthe convex side faces the burner and forms anupwardly and outwardly deflecting surface which. becomes heatedintensely. The llame dellector is supported in position by means ofradially extendingarms 11 projecting from the periphery thereof andextending through slots 18 in the burner bowl. Cooperating with thesemispherical portion of the burner bowl and encircling the flange 1| isan inner bowl 19 closely contacting the burner bowl and having openings80 therein registering with the air inlet openings 18; The rim of theinner member has corrugations 82. corresponding to the corrugations 1.4previously described.

In order to control movement of combustion supporting air, limitexternal cooling effects on the burner bowl, and prevent drafts frominterfering with operationtof'theflame, the portion-of is operated by arock shaft 82 rotatably suppbrted in a laterally extending arm 83 o fthe valve body. The .shaft extends through a packing 84 `con-- tained ina shouldered bore 88 of the arm and which is pressed in sealing contactwith the rock shaft by a packing gland 98. The inner end of therockslaft has a crank arm 31 having a pin portion 88 engaged in atransverse groove 88 formed in the head 88 of the clean-out device sothat when the shaft is rotated the needle 9| is moved through the outletorifice 8l to clear it of any matter that may be lodged therein. The endin Fig. 1f.

of the rock shaft projecting outwardly from the packing gland is bentlaterally to provide a handle |00 by which it is readily oscillated.

Air pressure is supplied to the fuel tank through the Acontrol valvewhen the valve is open and to effect atomization when starting theburner. The air is'supplied by means of a pump r|0| carried by the top'of the tank and havinga barrel portion projecting thereinto. Thepressure outlet of the pump has connection with the air space above thefuel through a duct |02 as shown Contained in the pump barrel is aplunger (not shown) whichA is actuated by a plunger rod |03 carrying anactuating knob |04.

In operating the burner'constructed and assembled as described, a. fuel,for example an ordinary automotive gasoline, is poured into the tankthrough the filler neck I up to the outlet end thereof, which leavesthe'air space 29 in the I top of the tank. The control valve 8 is closedand thevplunger rod |03 of the pump |0| is actuatedto build up pressurewithin the tank to force shaft 92 with the handle |00 to raise and lowerthe needle 0| through the orifice 84 of the nozzle tip. The controlvalve is then opened slightly, whereupon liquid "in the tank isdischarged through the inlet orifice 28, which, .because of the throttlerod 49, is a relativelysmall quantity, to produce a readily ignitedVmixture with the air passing from the tank downwardly through the nvannular space 28 between the tubes 2l and 21.

The mixture 'is discharged upwardly through the valve body and vaporizertube at suillciently high velocity and pressure to be discharged vfromthe nozzle tip in-a une mist, which is readily ignited to start theburner. The resultant flame plays against the deector and is directedoutwardly upon the inner surface of the flaring portion of the burnerbowl to heat the metal thereof and cause anupdraft of'air from the lowerend of the tubular shield 83 through the open;

ings 18 and 80, into the burner bowl, and through Y in close relationwith the vaporizer tube to coo operate with the heat conductivecapacities thereof in maintaining `lthe desired predetermineduniformtemperature ofthe vaporizer walls. r

In 'order to vassist in vaporization of the fuel,

` the vaporizing chamber has a plurality of layers umm external commeeaeets on the bowl The the passage 84 formed between the deflector 18and flaring portion of thebowl. It will be ntedthat the portionfofthe-shield .which enclrcles the flame contacting portion ofthe burnerbowl.

heat is conducted downwardly through the semispherien portion ofthe.bowl te tne'eene u thereof and through' the threaded connection into.the thickened wallportion 88 ofthe vaporlzer tube, the rate of heatconduction being controlled, as above stated, by the extent of engage-Qmentor the collar with the vaporlzer tube and" in me name 4 Y ithethi'ckness ofthe metal of the burner bowl so that the heat is utilized to cause vaporization of the lower boiling point fractions ofthefuel mixture passingthrough the vaporizing chamber. As -soon as gasbegins to,..discharge into the burner delivered from the tank -into'thevaporizer tube.

' I iind that ordinary leadedmotor or automotive fuels may be lpreheatedto approximately 400 F. fand `under some-conditionsmay befraised to 450iitviiiliiiit sppreciablelistillationfof the heavier fractions whichcontain .the objectionable gums A asaaoss l i be heated .syfepmbusaawnmnthe vbnrnerbowi and having a limited'portion in variable heat `vconductive contact with said thick-wall portion of'l the' vaporizer forconducting an amount of heat necessary to maintain the fuel within thevaporizer at a vanorizing temperaturev below the decomposing point ofsaid compound so that the compound 'is discharged into the burner bowlwithout being decomposed in the vaporizer, a

and lead. The tetraethyl lead content ,becomes f volatile at thesecqmparativ low temperatures and does not begin to separate and'fon'nsolid depositsuntil the ltemperature reaches 400 F.

, and under operating pressure might rise to450' Vvthrough the orificeof said nozzle tip.

clean-out needle supported in the vaporizer, and means for selectivelylprojecting the needle 2. An apparatus for burning liquid hydrocarbonfuel containing acompound which produces objectionable depositswhen'saidi compound is heated to decomposing tempeature.- including aburner for burning said fuel 'nd having an air inlet to supplycombustion supporting air ,into

the burner, a vaporizer vhaving an externally threaded end, a fueldischarge nozzle projecting from said end of the vaporizer to dischargefuel F. Therefore, since the burner structure is delsigned to maintain avaporizer temperature between 400 and 450 F. it is not hot enough toeffect vaporlzatiorr of the higher boiling point fractions -of the fuelor break down ofthe tetra- .ethyl lead compound, consequently theseparts are dischargedfrom the vaporizer in the form of atcmized liquidinto burning vapor resulting from the Vaporized lower boiling pointfractions. It is thusv obvious that the portions of the fuel ordinarilytending to clog the burner cannot break down until they have reached thehotter zone in the burner bowl where they are readily consumed ndsubstantially complete combustion is effected. The flame playing againstthe deflector soon brings the metal to an intense heat.

It is obvious that the partially vaporized fuel is delivered upon thesuperheated deector plate with considerable force and at atmosphericpressure, which assures complete vaporization and causes dissipation ofany solid particles thatv might be formed in the burner bowl.

The deected'ame playing upon the viared lwall of the burner bowlsupplies heat to the vaporizer almost entirely through conduction andsince the movement of combustion supporting air through the burner issubstantially constant, the temperature 'of the vaporizer is keptapproximately uniform and cannot reach the point where the objectionableelements are deposited in lthe vaporizing chamber and-clog the oriilceof the needle tip. Should any objectionable matter be deposited it is solight and lnilnitesimal that the orice of the nozzle -tipis readilycleared into the burner, means for supplying said lfuel to the vaporizerfor discharge into the burner, and

a collar having heat conductive connection with the burner to conductheat of combustion within the burner and having c threads engaging thethreaded end of the` vaporizer toh conduct said heat to the vaporizer,said collar being adjustable to vary the extent of engagement of thethreads so that heat may be conducted in an amount substantiallyproportional to the extent of engagement of said threads for maintainingthe fuel within the vaporizer at a Vaporizing temperature below thedecomposing pointl of said compound so that the compound is dischargedinto the burner without being decomposed With- I inthe vaporizer.

3. An apparatus for burning liquid hydrocarbon fuel containing a portionwhich produces. objectionable depositsl when heated to decomposingtemperature, including an open 'top burner bowl for burning said fueland having an air inlet to supply combustion supporting air into theburner bowl for maintaining combustion of fuel within the burner bowl, avaporizer having an outlet discharging into the burner bowl, means l forsupplying the liquid hydrocarbon fuel to the vaporizer under pressure,fuel atoinizing means thereof by the cleaning needle. Therefore thevaporizer will operate overa long period of time without repair orreplacement even'though automotive fuels are used in the stove.

What I claim and desire to secure by Letters Patent is:

Al. An'apparatus for burning liquid hydrocarbon fuel containing acompound which produces objectionable deposits when said compound isheated to decomposing temperature, including a lburner bowl for burningsaid fuel and having an air inlet to supply combustion supporting airinto the burner bowl; a vaporizer having a nozzle tip provided with afuel outlet orice arranged to discharge into the burner bowl, means forsupplying said fuel to the vaporizer, said vaporizer having a thick wallportion surrounding the nozzle tip and spaced from the outlet orifice,heat conducting means having a portion in position to cooperating withthe fuel supply means for initially delivering'air with the fuel foratomizing said fuel discharged into the burner bowl during startingoperation to initially heat the burner bowl, and a heat conductiveconnection between the burner bowl and .said vaporizer to conduct apredetermined amount ofl heat from the burner bowl to the vaporizer forheating the fuel within the vaporizer to a temperature below thedecomposing point of said objectionable portion of the fuel and sumcientto vaporize portions of the fuel having a lower distillation pointwhereby the objectionable y portion is discharged from. the vaporizerinto the burner bowl in substantially liquid form and said otherportions in vapor form for continuing operation of said apparatus.

,'4. An apparatus for burning liquid hydrocarbon fuel containing aportion which produces objectionable deposits when heated to decomposingtemperature, including an open' top burner bowl for burning said fueland having an air inlet to supply combustion supporting air into theburner bowl for maintaining combustion of fuel within the burner bowl, avaporizer having an outlet clischarging into the burner bowl, means forsupplying the liquid hydrocarbon fuel to the vaporizer under pressure,fuel atomizing means cooperating with the fuel supply means forinitially delivering air with the fuel foi` atomizingsaid fueldischarged into the burner b`owl during starting operation to initiallyheat the burner bowl.and a collar having heat conductive connection withthe burner bowl and engagement with a' limited portion of said vaporizerbelowrsaid outlet to 'conduct a pref determined amount of heatv from theburner bowl to the vaporizer for heating fuel within the valingtemperature, including an open top burner bowl for burning said fuel andhaving an air inlet to supply combustion supporting air into the burnerbowl for maintaining combustion of fuel within the burner bowl,l avaporizer having an outlet discharging into the burner bowl, means forsupplying the liquid hydrocarbon fuel to the vaporizer under pressure,fuel atomizing means cooperating with the fuel supply'means forinitially delivering air-with the fuel for atomizing said fueldischarged into the burner bowl during starting operation to initiallyheat the burner bowl, 'a'ame deector, means supporting theflamedeflector within the open top of the burner bowl to deflect flameresulting from combustion of said atomized fuel into contact-with anupper portion of the burner bowl to'initially heat the burner bowl, and'a heat conductive connection between the burner bowl and said vaporizerto conduct -a predetermined amount of said heat from the burner bowl tothe vaporizer for heating fuel within the vaporizer tba temperaturebelow thedecomposing point of said objectionable portion of the fuel andsuiiicient to vaporize portions of they fuel having a lower distillationpoint whereby the objectionable portion is discharged from the vaporizerinto the burner bowl'in substantially liquid form and other portions ofthe fuelin vapor form for continuing operation of said apparatus.

6. An apparatus for burning liquid hydrocarbon fuel containing a portionwhich produces objectionable deposits when heated to decomposingtemperature, 'including' an open top burner bowl for burning said` fueland having an air inlet to supply combustion supporting air into thebuiner bowl for maintaining combustion of fuel within the burner bowl,'a vaporizer having an,

outlet discharginginto 'the burner bowl, means 'for supplying the liquidhydrocarbon fuel to the vaporizer under pressure, fuel -atomiaing meanscooperating with the fuel supply means for initial'y delivering, airwith the fuel for atomizing `and suiliclent to vaporize portions of thefuel having alower distillation pointwhereby the objectionable portionis discharged from the vaporizer' into the burner bowl in substantially/liquid form and said other portions in vapor form forv continuingoperation of said apparatus, and a shield encircling the burner bowl forlimiting external cooling effects on said burner bowl.

7. An` apparatus for burning liquid hydrocarbon fuel containing aportion which produces objectionable deposits when heated to decomposingtemperature, including an open top burner bowl for burning said fuel andhaving an air -inlet to supply combustion supporting air into the burnerbowl foi-.maintaining combustion of fuel within the burner bowl, avaporizer .having an outletgdischargingtinto the burner bowl, means forsupplying the liquid hydrocarbon fuel to the vaporizer under pressure,`fuel atomizing means cooperating with the fuel supply means forinitially delivering air with the fuel for atomizing vsaid 4fueldischarged into'the burner bowl during l starting operation to initiallyheat the burner bowl, a flame deflector, means supporting the flamedeflector within the open top of the burner bowl to deect flameresulting from combustion of said atomized fuel into contact with anupper portion of the burner b owl to initially heat the burner bowl, aheat'conductive connection between the burner bowl and said vaporizer toconduct a predetermined amount of said heat from the burner bowl to thelvaporizer for heating fuel bowl contacted by said flame for limitingexternal cooling effects on said burner bowl.`

8. An apparatus for burning liquid hydrocar-A bon fuel containing acompound which produces objectionable deposits when said compound isheated to decomposingtemperature including, r

an open top burner bowl-for 4burning said fuel and having air air inletto supply combustion supporting air Aint'o the burner bowl, a vaporizerhaving an outlet for discharge into the burner bowl, means for supplyingsaid fuel to the vaporlzer for discharge into the burner bowl, heatconductive means connecting the burner bowl with a limited portion ofsaid vaporizerI for. conencircling the portion of the burner bowl connresulting from combustion of fuel in the burner y bowlfor deilecting theflame into contact with an upper portion of the burner bowl, and ashield to decomposing temperature including, an open top burner bowl'forburnirm said fuel and having an air inlet to supply combustionsupporting air into the burner bowl, a vaporizer having an outlet fordischarge into the burner bowl, means for `supplying said fuel to thevaporizerfor discharge he t from the burner bo'wl'to'the vaporizernec--4 4 to maintain'the temperature of yfuel 4Within thelveporizerbeiowthedecomposing temper-` ature of said compound so that the compoundis di'sciarged limo the burner bowl without being decomposed in thevaporizer. a llame defiector located m the borner bowl within themen cfmmeente "y v t l discharge from the vaporizex" enclin position to becontacted by the'fiame resulting from combustion of fuel within theburner for detecting-the flame into contact with an upper portion of theburner bowl, and a shield encircling the portion otthe burner bowlcontacted by said fime and depending below Zsaid heat conductive meansfor limiting external cooling effects on'said heat conductive means.

